• Type: Correctness / Convergence robustness
• Severity: Medium
• Component: MLCurlCurl 1D smoother
• Location:
  • Src/LinearSolvers/MLMG/AMReX_MLCurlCurl_K.H:567
  • Src/LinearSolvers/MLMG/AMReX_MLCurlCurl_K.H:649

Problem

In coord == 1 path, the scalar-beta smoother updates the axis value on both red/black passes (i==0 || i==1), but the variable-beta overload updates it only for i==0.

That asymmetry strongly suggests copy-paste drift between the two overloads.

Impact

• Different smoother dynamics between constant- and variable-coefficient paths.
• Potential convergence-rate regression and sweep asymmetry for cylindrical 1D runs with spatially varying beta.

Suggested patch

Match the variable-beta path to the scalar-beta update condition so both color sweeps refresh the axis value.

--- a/Src/LinearSolvers/MLMG/AMReX_MLCurlCurl_K.H
+++ b/Src/LinearSolvers/MLMG/AMReX_MLCurlCurl_K.H
@@
-            if (i == 0) {
+            if ((i == 0) || (i == 1)) {
                 ez(0,0,0) = (rhsz(0,0,0) + Real(4.0)*dxx*ez(1,0,0)) / (betaz(0,0,0) + Real(4.0)*dxx);
             } else if (! dinfo.is_dirichlet_node(i,j,k)) {
                 Real cm = dxx * (Real( 0.5)/Real(i) - Real(1.0));
                 Real cp = dxx * (Real(-0.5)/Real(i) - Real(1.0));

Prepared by Codex